22 documents found, page 1 of 3
Impact of the Curing Temperature on the Manufacturing Process of Multi-Nanopart...
Parente, João M; Simões, Rogério S.; Silva, Abilio P; Reis, Paulo N. B.This study aims to analyze the effect of the curing temperature of nano-reinforcements during the manufacturing process on the mechanical properties of composites involving graphene (GNP), carbon nanofibers (CNFs), and a hybrid mixture of these two nanoparticles. In this context, the type of nanoparticles, their content, their type of resin, and their hybridization were considered. The results showed that both ...
Effect of annealing treatment on mechanical properties of 3D-Printed composites
Valvez, Sara; Reis, Paulo N. B.; Ferreira, José A. M.This study aims to analyse the annealing effect on the mechanical properties of PETG, carbon fibre reinforced PETG (PETG þ CF) and Kevlar fibre reinforced PETG (PETG þ KF). Regardless of the material, the final dimensions vary with temperature and exposure time, showing that the addition of fibres had no significant influence. On the other hand, the presence of fibres affects the radius of curvature, but this p...
Effect of Carbon Nanofibers on the Viscoelastic Response of Epoxy Resins
Santos, Paulo; Silva, Abílio P.; Reis, Paulo N. B.Two epoxy resins with different viscosities were enhanced up to 1 wt.%, applying a simple method with carbon nanofibers (CNFs). These were characterized in terms of static bending stress, stress relaxation, and creep tests. In bending, the contents of 0.5 wt.% and 0.75 wt.% of CNFs on Ebalta and Sicomin epoxies, respectively, promote higher relative bending stress (above 11.5% for both) and elastic modulus (13....
Thermal Study of Carbon-Fiber-Reinforced Polymer Composites Using Multiscale Mo...
Nasri, Wiem; Driss, Zied; Djebali, Ridha; Lee, Kyu-Yeon; Park, Hyung-Ho; Bezazi, Abderazak; Reis, Paulo N. B.The layered fibers of carbon-fiber-reinforced polymer (CFRP) composites exhibit low thermal conductivity (TC) throughout their thickness due to the poor TC of the polymeric resin. Improved heat transmission inside the hydrogen storage tank during the filling process can reduce further compression work, and improved heat insulation can minimize energy loss. Therefore, it is crucial to understand the thermal prop...
Effect of Cohesive Properties on Low-Velocity Impact Simulations of Woven Compo...
Ferreira, Luis M.; Coelho, Carlos A. C. P.; Reis, Paulo N. B.The effect of the interface stiffness and interface strength on the low-velocity impact response of woven-fabric semicylindrical composite shells is studied using finite element (FE) models generated with continuum shell elements and cohesive surfaces. The intralaminar damage is accounted for using the constitutive model provided within the ABAQUS software, while the interlaminar is addressed utilising cohesive...
Effect of Carbon Nanofibers on the Strain Rate and Interlaminar Shear Strength ...
Santos, Paulo; Silva, Abílio P; Reis, Paulo N. B.The static bending properties, different strain rates and interlaminar shear strength (ILSS) of carbon-fiber-reinforced polymers (CFRP) with two epoxy resins nano-enhanced with carbon nanofibers (CNFs) are studied. The effect on ILSS behavior from aggressive environments, such as hydrochloric acid (HCl), sodium hydroxide (NaOH), water and temperature, are also analyzed. The laminates with Sicomin resin and 0.75...
Numerical Simulations of the Low-Velocity Impact Response of Semicylindrical Wo...
Ferreira, Luis M.; Coelho, Carlos A. C. P.; Reis, Paulo N. B.This paper presents an efficient and reliable approach to study the low-velocity impact response of woven composite shells using 3D finite element models that account for the physical intralaminar and interlaminar progressive damage. The authors' previous work on the experimental assessment of the effect of thickness on the impact response of semicylindrical composite laminated shells served as the basis for th...
Static and Fatigue Characterization of Adhesive T-Joints Involving Different Ad...
Serra, Georgino C. G.; Ferreira, José A. M.; Reis, Paulo N. B.It is very important to understand the damage mechanisms as well as the mechanical response of T-joints involving different materials on the base plate. For this purpose, two configurations were studied. In one, the joint is composed of a base plate and a T-element, both in Al 6063-T5, while in the other one, the aluminum base plate was replaced by a glass fiber composite. Finally, each configuration was divide...
Flexural performance of squared one-sided CFRP patches: modelling and experimen...
Abdelfattah, Ibrahim; Ferreira, Francisca; Nasr Saleh, Mohamed; Reis, Paulo N. B.; Freitas, Sofia Teixeira deThree-point bending analysis, experimental and numerical, is conducted for three different sizes, 30*30 mm, 40*40 mm and 60*60 mm, of one-sided square cross-ply TEXIPREG HS 160 RM carbon-fiber-reinforced polymer (CFRP) patches as well as intact and notched specimens. The tests are carried out with the aim to study the influence of the patch’s size on the flexural properties of the specimen. Hashin-2D damage ini...
Compressive Behaviour of 3D-Printed PETG Composites
Valvez, Sara; Silva, Abílio P.; Reis, Paulo N. B.It is known that 3D-printed PETG composites reinforced with carbon or Kevlar fibres are materials that can be suitable for specific applications in the aeronautical and/or automotive sector. However, for this purpose, it is necessary to understand their mechanical behaviour, which is not yet fully understood in terms of compression. Therefore, this study intends to increase the knowledge in this domain, especia...